Archived 2016 topics: Tit-like Dacnis (Xenodacnis parina) is being split: request for information.

This is part of a consultation on the Red List implications of extensive changes to BirdLife’s taxonomy for passerines

Lynx Edicions and BirdLife International will soon publish the second volume of the HBW-BirdLife Illustrated Checklist of the Birds of the World, building off the Handbook of the Birds of the World series, and BirdLife’s annually updated taxonomic checklist.

The new Checklist will be based on the application of criteria for recognising species limits described by Tobias et al. (2010). Full details of the specific scores and the basis of these for each new taxonomic revision will be provided in the Checklist.

Following publication, an open and transparent mechanism will be established to allow people to comment on the taxonomic revisions or suggest new ones, and provide new information of relevance in order to inform regular updates. We are also actively seeking input via a discussion topic here regarding some potential taxonomic revisions that currently lack sufficient information.

The new Checklist will form the taxonomic basis of BirdLife’s assessments of the status of the world’s birds for the IUCN Red List. The taxonomic changes that will appear in volume 2 of the checklist (for passerines) will begin to be incorporated into the 2016 Red List update, with the remainder to be incorporated into subsequent Red List updates.

Preliminary Red List assessments have been carried out for the newly split or lumped taxa. We are now requesting comments and feedback on these preliminary assessments.

Tit-like Dacnis Xenodacnis parina is being split into X. parina and X. petersi, following the application of criteria set out by Tobias et al. (2010).

Prior to this taxonomic change, X. parina was listed as Least Concern, on the basis that it did not approach the threshold for Vulnerable under any criterion. X. parina (as now defined following the taxonomic change) and X. petersi are found at and above the tree-line, and the pre-split species was more associated with Polylepis woodland compared to non-wooded matrix habitats (Lloyd and Marsden 2008, Hilty 2016), although Gynoxys shrubs may be the most important plant (Hilty 2016). X. parina is found in southern Peru on the eastern slope of the Andes, as well as on the western slope near Arequipa. X. petersi is found further north, on the western slope of the Andes in Peru, north of Lima, and in northern central Peru. An uncertain race in southern Ecuador is also incorporated into this taxon (see Hilty 2016). The Polylepis habitat is under intense pressure as there is widespread destruction of this habitat from firewood collection, uncontrolled fire, agriculture, grazing and afforestation with exotic trees (Fjeldså and Kessler 1996, Stattersfield et al. 1998), and so both species may be declining and becoming fragmented in line with the loss of their habitat.

Both of the newly defined species have sufficiently large Extents of Occurrence to not approach the threshold for Vulnerable under criterion B, and based on descriptions of abundance, range size, known records, population density estimates for closely related species and assuming only a proportion of their ranges are occupied, both species likely contain sub-populations the exceed 1,000 mature individuals, and so do not meet the threshold for listing under criterion C2a(i).

We welcome any further information regarding potential rates of Polylepis loss to ascertain whether these species may be undergoing a decline of or approaching 30% over 3 generations (c. 11 years). In the absence of this information these species may require listing as Least Concern.

References:

Fjeldså, J. and Kessler, M. 1996. Conserving the biological diversity of Polylepis woodlands of the highland of Peru and Bolivia. NORDECO, Copenhagen.

Hilty, S. 2016. Tit-like Dacnis (Xenodacnis parina). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/61758 on 18 October 2016).

Lloyd, H. and Marsden, S.J. 2008. Bird community variation across Polylepis woodland fragments and matrix habitats: implications for biodiversity conservation within a high

Stattersfield, A. J., Crosby, M. J., Long, A. J. and Wege, D. C. 1998. Endemic bird areas of the world: priorities for bird conservation. BirdLife International, Cambridge, U.K.

Tobias, J. A., Seddon, N., Spottiswoode, C. N., Pilgrim, J. D., Fishpool, L. D. C. and Collar, N. J. 2010. Quantitative criteria for species delimitation. Ibis 152: 724–746.

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One Response to Archived 2016 topics: Tit-like Dacnis (Xenodacnis parina) is being split: request for information.

  1. James Westrip (BirdLife) says:

    Based on available information, our preliminary proposal for the 2016 Red List would be to list both species as Least Concern.

    There is now a period for further comments until the final deadline of 28 October, after which the recommended categorisations will be put forward to IUCN.

    Please note that we will then only post final recommended categorisations on forum discussions where these differ from the initial proposal.

    The final 2016 Red List categories will be published on the BirdLife and IUCN websites in early December, following further checking of information relevant to the assessments by both BirdLife and IUCN.

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